Disappearing button or slider

ABSTRACT

An input device is operable to detect input. The input device is a deflection based capacitive sensing input device. Deflection of a metal frame of the input device causes a change in capacitance that is used to control a function of an electrical device. The input device appears invisible because it is made of the same material as the housing it is contained in. Invisible backlit holes may make the input selectively visible or invisible to the user.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/282,375, entitled “Disappearing Button or Slider,” filed on May 20,2014, now U.S. Pat. No. 9,400,579, which is a continuation of U.S.patent application Ser. No. 13/888,579, entitled “Disappearing Button orSlider,” filed on May 7, 2013, now U.S. Pat. No. 8,786,568, which is acontinuation of U.S. patent application Ser. No. 12/257,956, entitled“Disappearing Button or Slider,” filed on Oct. 24, 2008, now U.S. Pat.No. 8,436,816, all of which are incorporated by reference in theirentirety as if fully disclosed herein.

This application is related to U.S. patent application Ser. No.11/551,988 filed Oct. 30, 2006, titled “INVISIBLE, LIGHT-TRANSMISSIVEDISPLAY SYSTEM,” and assigned to the assignee of the presentapplication. The Ser. No. 11/551,988 application is acontinuation-in-part of U.S. patent application Ser. No. 11/456,833filed Jul. 11, 2006 titled “INVISIBLE, LIGHT-TRANSMISSIVE DISPLAYSYSTEM,” and assigned to the assignee of the present application. TheSer. No. 11/551,988 and the Ser. No. 11,456,833 applications are bothherein incorporated in their entirety by reference thereto.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to input devices and devicedisplay systems, and more particularly to invisible input systems anddevice display systems. The input devices and display systems may becomevisible when illuminated from behind through invisible holes.

2. Background Art

In the world of consumer devices, and particularly consumer electronics,there is an ever-present demand for improved appearance, improvedfunctionality, and improved aesthetics. Industrial design has become ahighly skilled profession that focuses on fulfilling this need forenhanced consumer product appearance, functionality, and aesthetics.

One area that receives attention for improvement, particularly inconsumer electronics, is user input and interface. Presently thereexists a range of mechanically actuated (e.g., buttons, switches,levers, keys, keyboards, dials, click wheels, scroll wheels, and thelike) or electrically actuated (e.g., touch pads, track pads, touchscreens, multi-touch screens, and the like) input devices. These inputdevices interface with their associated electronic devices (e.g.,computers, laptop computers, media devices, mobile phones, calculators,medical devices, etc. . . . ) in order to control a function of thedevice, for example, turn the device on or off, open a menu, move acursor and so forth.

One challenge with these known input devices is that they may detractfrom the aesthetics of the device by interrupting the continuity of thedevice housing. To illustrate, compare a mobile phone having atraditional key pad with the iPhone produced by Apple Inc. of Cupertino,Calif. The iPhone has a flat touch-sensitive screen which presents astriking, seamless design, while the traditional mobile phone presents acluttered array of keys and buttons. Besides the obvious aestheticadvantages of having a seamless design, a seamless design may haveimproved functionality and/or durability. For example, a traditionalmechanical key pad can wear out over time and/or be ruined by dirt ormoisture entering into the openings in the device housing. Theseopenings are necessary to accommodate the traditional keys and buttons.

The iPhone touch screen uses capacitive sensing. This type of sensingtakes advantage of the fact that two electrical fields separated by adielectric produce capacitance. In the iPhone, a first electrical fieldis produced inside the iPhone by an array of electrodes. The secondelectrical field is provided by the user's finger. When the fingerinteracts with the glass touch surface a circuit inside the iPhonedetects a change in capacitance and processes this change in order tocompute, for example, the location and speed of the scrolling finger.Some modem track pads on laptop computers may function in a similar way,but normally have plastic or rubber track surfaces. In all of thesedevices the housing of the device is normally metal, while the tracksurface is normally a dielectric material such as rubber, plastic, orglass. Therefore, a truly seamless design has been impossible.Furthermore, a glass surface may be fragile.

Taken to its extreme, seamless design would have an invisible input.Since a metal housing is advantageous for aesthetic, environmental, andmanufacturing reasons, this presents a particular challenge. One methodto overcome this challenge is to include a plastic input painted to looklike metal. However, this will not match the metal look and finishexactly, so the truly seamless design is not realized.

Another area that continually receives great attention for improvementis user displays. Providing crisp, attractive, unambiguous, andintuitively friendly displays and information for the user is veryimportant in many consumer products. However, as consumer productsconstantly become smaller and smaller, and in some cases more and morecomplex, it becomes increasingly difficult to present and display userinformation in a manner that is easy for the user to grasp andunderstand, but is also in an uncluttered form and appearance that isaesthetically pleasing.

Much of the aesthetic appeal of a consumer product can quickly becompromised if there are too many display elements, or if too muchdisplay area is occupied by display elements that are not needed exceptat particular times. When not needed, these “passive” or unactivateddisplay elements invariably remain visible to the user, even though theyare in the “off” state. This is not only displeasing from an aestheticstandpoint, but it can be an annoying distraction that interferes withdetection and understanding of other display elements that need to beobserved at a given moment.

Illuminating display elements is known. Some display elements areilluminated continuously; others are illuminated only when appropriateto instruct and guide the user. Display elements that are notcontinuously illuminated can still be distracting, or at leastaesthetically objectionable, when not illuminated (when in the offstate) because they may still remain visible in the display area.

For example, one typical such display element is configured fromtransparent plastic inserts that penetrate through the metallic case ofan electronic device, and are smoothly flush with the outer surface ofthe case. A large number of such always-visible display elements leadsto a cluttered, confusing, and unattractive appearance. In fact, even asingle such element, when not illuminated (i.e., in an inactive state),can become an unattractive distraction on an otherwise smooth andattractive surface.

Less expensive device housings, for example, those made of opaqueplastic rather than metal, are often similarly provided with transparentplastic inserts for illuminated display elements. These display elementsalso conflict with a good aesthetic appearance when they are notilluminated. Also, displays using plastic or glass are less durable thanmetal and are more subject to breaking or cracking.

Additionally, the separate visible inserts utilized by prior techniquessometimes do not fit perfectly in the holes in which they are insertedor formed. Such imperfect fit can invite entry of liquids, dirt, and thelike, undesirably causing yet another disadvantage.

Thus, the need exists for commercially feasible device display systemswith improved aesthetics that unobtrusively furnish information asappropriate, but otherwise do not distract or detract from the user'sexperience or the device's performance. Preferably, selected elements ofsuch display systems would additionally become invisible in their offstates.

In view of ever-increasing commercial competitive pressures, increasingconsumer expectations, and diminishing opportunities for meaningfulproduct differentiation in the marketplace, it is increasingly criticalthat answers be found to these challenges. Moreover, the ever-increasingneed to save costs, improve efficiencies, improve performance, and meetsuch competitive pressures adds even greater urgency to the criticalnecessity that answers be found.

BRIEF SUMMARY OF THE INVENTION

The invention relates in one embodiment an electronic device having aninvisible input. The device has a frame having a top face with invisibleholes formed therein. A capacitor reference is on an inner surface ofthe top face in the area of the invisible holes. An interior wall isseparated from the top face and forms an interior space having adielectric medium disposed therein. A capacitor plate is disposed on asurface of the interior wall opposite the first capacitor plate. A lightsource is disposed in the interior space and is configured to shinethrough the invisible holes. A capacitor sensor is electricallyconnected to the capacitive reference and the capacitor plate. When anobject is placed on the frame in the area of the invisible holes andpressure is applied, the frame deforms. This deformation causes a changein capacitance between the capacitive reference and the capacitor plate.The capacitor sensor detects this change and converts it to anelectrical signal.

The invention relates in another embodiment to an invisible input. Theinvisible input has a frame having a top face with invisible holesformed therein. A capacitor reference is on an inner surface of the topface in the area of the invisible holes. An interior wall is separatedfrom the top face and forms an interior space having a dielectric mediumdisposed therein. A capacitor plate is disposed on a surface of theinterior wall opposite the first capacitor plate. A light source isdisposed in the interior space and is configured to shine through theinvisible holes. A capacitor sensor is electrically connected to thecapacitive reference and the capacitor plate. When an object is placedon the frame in the area of the invisible holes and pressure is applied,the frame deforms. This deformation causes a change in capacitancebetween the capacitive reference and the capacitor plate. The capacitorsensor detects this change and converts it to an electrical signal

BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES

Certain embodiments of the invention have other aspects in addition toor in place of those mentioned above. The aspects will become apparentto those skilled in the art from a reading of the following detaileddescription when taken with reference to the accompanying drawings. Thepresent invention is illustrated by way of example, and not by way oflimitation, in the figures of the accompanying drawings and in whichlike reference numerals refer to similar elements and in which:

FIG. 1 is a perspective view of an electronic device according to thepresent invention;

FIG. 2 is a cross sectional view of the electronic device of FIG. 1,taken along line 2-2 in FIG. 1 in a first position;

FIG. 3 is another cross sectional view of the electronic device of FIG.1, taken along line 2-2 in FIG. 1 in a second position;

FIG. 4. is a cross sectional view of an alternate embodiment of theelectronic device of FIG. 1;

FIG. 5A is a perspective view of an embodiment of the electronic deviceof FIG. 4;

FIG. 5B is a magnified view of a portion of the electronic device ofFIG. 5A;

FIG. 6 is a perspective view of another electronic device according tothe present invention;

FIG. 7 is a cross sectional view of the electronic device of FIG. 6,taken along line 7-7 in FIG. 6 in a first position;

FIG. 8 is another cross sectional view of the electronic device of FIG.6, taken along line 7-7 in FIG. 6 in a second position;

FIG. 9 is another cross sectional view of the electronic device of FIG.6, taken along line 7-7 in FIG. 6 in a third position;

FIG. 10. is a cross sectional view of an alternate embodiment of theelectronic device of FIG. 6;

FIG. 11 is a perspective view of an alternate embodiment of theelectronic device of FIG. 6;

FIG. 12 is a schematic of a conventional track pad;

FIG. 13 is a perspective view of an electronic device according to thepresent invention;

FIG. 14 is a schematic plan view of internal portions of the electronicdevice of FIG. 13;

FIG. 15 is a cross sectional view of the electronic device of FIG. 13,taken along line 15-15 in FIG. 13;

FIG. 16 is a schematic plan view of internal portions of the electronicdevice of FIG. 13;

FIG. 17 is a perspective view of an alternate embodiment of theelectronic device of FIG. 13;

FIG. 18 is a cross sectional view of another electronic device accordingto the present invention;

FIG. 19 is a cross sectional view of another electronic device accordingto the present invention;

FIG. 20 is a cross sectional view of another electronic device accordingto the present invention;

FIG. 21 is a cross sectional view of another electronic device accordingto the present invention;

FIG. 22 is a cross sectional view of another electronic device accordingto the present invention;

FIG. 23 is a cross sectional view of another electronic device accordingto the present invention;

FIG. 24 is perspective view of a laptop computer according to thepresent invention;

FIG. 25 is a front view of a laptop computer according to the presentinvention; and

FIG. 26 is a front view of a laptop computer according to the presentinvention.

DESCRIPTION OF THE INVENTION

The present invention will now be described in detail with reference toa few preferred embodiments thereof as illustrated in the accompanyingdrawings. In the following description, numerous specific details areset forth in order to provide a thorough understanding of the presentinvention. It will be apparent, however, to one skilled in the art, thatthe present invention may be practiced without some or all of thesespecific details. In other instances, well known process steps have notbeen described in detail in order not to unnecessarily obscure thepresent invention.

Likewise, the drawings showing embodiments of the system aresemi-diagrammatic and not to scale and, particularly, some of thedimensions are for the clarity of presentation and are shown greatlyexaggerated in the drawing figures.

Similarly, although the views in the drawings for ease of descriptiongenerally show similar orientations, this depiction in the figures. isarbitrary for the most part. Generally, the invention can be operated inany orientation. In addition, where multiple embodiments are disclosedand described having some features in common, for clarity and ease ofillustration, description, and comprehension thereof, similar and likefeatures one to another will ordinarily be described with like referencenumerals.

Referring now to FIG. 1, a generic electronic device 10 is shown. Device10 could be, for example, a laptop computer, a media device, a remotecontrol, a game player, or any other device that requires a button orswitch. Device 10 features an invisible button or switch 20, whoselocation is shown in phantom. Button 20 is used to control some functionassociated with electronic device 10. Device 10 has a metal frame 30,which may be, for example, aluminum. Button 20 is invisible because itis made from and integral with the same metal as frame 30. Button 20 isflush with and does not bulge out or otherwise protrude into or out offrame 30. Therefore, it is not visible from the exterior of device 10.Frame 30 may have markings (e.g., paint, texture) to indicate thelocation of button 20.

FIG. 2 shows a side cross sectional view of device 10, taken along line2-2 shown in FIG. 1. Metal frame 30 has a face 40. Inside of device 10,there is an interior wall 50 below face 40. In between face 40 and wall50 is a dielectric medium 60, such as air. In another implementation,dielectric medium 60 can be foam or rubber. In these implementations,supports 70 could be unnecessary and therefore removed. Supports 70 aredisposed between face 40 and interior wall 50. Dielectric medium 60 canbe a dielectric gel (instead of air).

In the vicinity of invisible button 20, a capacitor plate 80 is disposedon an inner surface of face 40, and another capacitor plate 85 isdisposed on a top surface of interior wall 50 opposite plate 80.Capacitor plates 80 and 85 may be attached to, for example, printedcircuit boards (PCBs) which are disposed on face 40 and/or wall 50. Inone embodiment, wall 50 is a PCB. In another embodiment, capacitorplates 80 and/or 85 can comprise conductive paint printed on face 40 andwall 50. As used herein, a “capacitor plate” could be any conductingmaterial which is separated from another conducting material. In theillustrated embodiment, capacitor plates 80 and 85 are shown as discreteobjects attached to face 40 and wall 50. In another embodiment (notshown) the face 40 and wall 50 themselves may function as capacitorplates.

There is a fixed separation between capacitor plates 80 and 85 whenbutton 20 is not being depressed. This is important because thecapacitance, C, between separated plates 80 and 85 is a function oftheir separation. When button 20 is not depressed, the zero-pressurecapacitance, C₀, is related to the initial separation of plates 80 and85. Departures from the initial separation will cause a change incapacitance, ΔC≡C−C₀, which can be detected and processed by device 10.In practice, C₀ may not be strictly a function of separation. Otherfactors, such as changes in temperature, humidity, age of components,and the like can cause minor fluctuations in C₀. Therefore, a newestimate or baseline for the zero-pressure C₀ may be updated. In oneembodiment, this update can be done each time device 10 starts up. Inanother embodiment, this update can be done during certain timeintervals (for example every few minutes). Updating C₀ helps to ensurehigher sensitivity and lower occurrences of false triggers.

When a user presses down on invisible button 20, face 40 deflectsbetween supports 70, as shown in FIG. 3. This causes the distancebetween capacitor plates 80 and 85 to decrease, creating an associatedchange in capacitance, ΔC. A capacitive sensor (not shown) associatedwith device 10 detects this change, and if the change is above somepreset threshold, T, a button function is activated. In other words ifΔC≥T the button function is activated. For example, when the userpresses down on button 20, device 10 may turn on or off. Since bothcapacitor plates 80 and 85 are internal to device 10, it is notnecessary to push button 20 with a conducting material, e.g., a fingeror stylus, as is the case with traditional capacitive sensing technology(e.g., glass touch screens). In contrast to traditional capacitivesensing surfaces, a user could successfully activate button 20 wearing anon-conductive glove, for example.

The on/off, or “binary,” mode of operation described above is thesimplest mode. In other embodiments, the change in capacitance ΔC couldbe correlated to a “continuous” output functionality. In thisimplementation, a larger ΔC could be associated with a command to fullintensity. A very small ΔC could be associated with a command to lowintensity. For example, how far the user presses down could correlate tohow bright to make a light, for example, how loud to play music, or howfast to go forward or backward in a movie. In this continuousfunctionality mode, the correlation between capacitor plate distance andchange in capacitance ΔC must be found through routine experiment,theory, calculation or combinations thereof. In other embodiments,button 20 could have three levels of functionality. This is a compromisebetween the binary and continuous modes. For example, before the userpresses down, device 10 is “off” when the user presses down a certainamount, device 10 operates at 50%, and when the user presses down acertain amount more, device 10 operates at 100%. This could mean thatdevice 10 could be used to turn a light from off, to 50% intensity, to100% intensity depending on user input. Of course, many variations ofthis multi-level functionality mode are possible (e.g., 4 or morelevels).

Supports 70 limit the area where a user can activate button 20. In theillustrated embodiment, if a user presses down to the left of the leftsupport 70, for example, capacitor plates 80 and 85 will not appreciablymove towards each other. Therefore, a change in capacitance (if any)will not exceed the threshold required to register a button depression,i.e., ΔC<T. The supports can be closely spaced, thereby making theeffective area of button 20 small, or the supports can be widely spaced,thereby making the effective area of button 20 large, as is shown in theillustrated embodiment. The configuration of supports 70 is shown forillustration only and may be widely varied. For example, there could betwo supports, as shown in the illustrated embodiment, or there could bemore than two supports, or only one support. In one embodiment (notshown), the entire surface 40 can function as button 20 if supports 70are removed. In this implementation, the outer vertical part of frame 30functions to keep face 40 and wall 50 separated when button 20 is notbeing depressed. Therefore, supports 70 are not necessary.

Supports 70 may be etched out of face 40 and/or wall 50 or they may befree standing. In one embodiment, Supports 70 are formed by etching thebottom surface of face 40 so that supports 70 extend downwardly. Inanother embodiment, supports 70 are formed by etching the top surface ofinterior wall 50 so that supports 70 extend upwardly. In anotherembodiment, face 40 and wall 50 and supports 70 are formed by etchingout parts of a monolithic piece. In another embodiment, free standingsupports 70 are affixed to face 40 and wall 50 by techniques known inthe art, for example adhesives, welds, fasteners, etc.

In some embodiments, it may not be desirable to have button 20 visibleor invisible all of the time. As previously mentioned, although frame 30may have markings (e.g., paint, texture) to indicate the location ofbutton 20, these markings would be visible all of the time and detractfrom the aesthetic simplicity of housing 30. To selectively control thevisibility of button 20, tiny invisible micro-perforations or holes 90can be formed in face 40 as shown in FIG. 4. Button 20 can beselectively backlit to highlight its location by, for example, shininglight through holes 90. In one embodiment, a light source, for example alight emitting diode (LED) 95 can be placed on wall 50 under thelocation of button 20. As shown in FIG. 5A, the location of button 20 isvisible LED 95 is activated.

In one embodiment, the backlight (e.g., LED 95) can be activatedwhenever electronic device 10 is “on.” In another embodiment, thebacklight can be activated as a function of an operating state of device10, for example, when a CD-ROM is inserted, when a memory stick isinserted, and so on, depending on the nature of electronic device 10. Inanother embodiment, the backlight can be activated as a function ofambient lighting conditions, for example, in low light (dark)conditions. In this embodiment, a light sensor (not shown) may interfacewith LED 95. In another embodiment, the backlight can be activatedcontinuously. In another embodiment, the backlight can be activated whena user taps or presses down on button 20. In another embodiment, amotion sensor (not shown) may interface with LED 95 and activate it whenmotion is detected. In another embodiments heat and/or sound sensors(not shown) can interface with and activate LED 95 when heat and/orsound is detected.

FIG. 5B is a magnified view of button 20 shown in FIG. 5A. A pattern 22of holes 90 can be disposed on frame 30 to indicate the borders ofbutton 20. This pattern can be formed by, for example, laser cuttingthrough frame 30. The holes 90, although shown greatly exaggerated inthe Figure, are actually invisible. That is, each of the holes 90 issmaller than resolvable by an unaided human eye. For example, the limitof resolution for the human eye is about 0.1 mm at a distance from theeye of 1 meter. In children, the resolution might be somewhat finer, forexample, 0.04 mm. Thus, depending upon the anticipated viewer andviewing distance, the holes 90 will be selected to be below the limit ofresolution, and it will accordingly be understood that the term“invisible hole” refers to this upper limit. Thus, as defined herein,“invisible holes” refers to holes that are smaller than resolvable by anunaided human eye. In one embodiment, the diameter of invisible holes 90can range from between 20 μm to 80 μm, inclusive. Light shining throughholes 90 is visible to the naked eye. This gives the impression thatbutton 20 can be made visible or invisible at will.

In another embodiment, the pattern of holes 22 can be made to resemblethe function of button 20, for example, the pattern can resemble atriangle to indicate a “play” function when controlling musicselections, or the pattern can resemble a square to indicate a “stop”function. In this way, when the backlighting is activated, a play orstop symbol appears on device 10 at the location of button 20. Inanother embodiment (not shown), pattern 22 can resemble text or numbers.Micro-perforated invisible holes 90 are explained in greater detail inU.S. patent application Ser. No. 11/551,988 filed Oct. 30, 2006, titled“INVISIBLE, LIGHT-TRANSMISSIVE DISPLAY SYSTEM,” and U.S. patentapplication Ser. No. 11/456,833 filed Jul. 11, 2006 titled “INVISIBLE,LIGHT-TRANSMISSIVE DISPLAY SYSTEM.” The Ser. No. 11/551,988 and the Ser.No. 11,456,833 applications are both herein incorporated in theirentirety by reference thereto.

As discussed above, button 20 is particularly suited to applicationsinvolving binary or on/off operations. Button 20 is also suited toapplications involving continuous output functions; but, as discussed, apossibly complicated correlation between button displacement and changein capacitance is necessary for button 20 to be able to control acontinuous output function. A simpler way to control a continuous outputfunction involves using multiple pairs of capacitive plates, as will bediscussed below.

Referring now to FIG. 6, a generic electronic device 100 is shown.Device 100 features an invisible “slider” or switch 110, whose locationis shown in phantom. Slider 110 is used to control some functionassociated with electronic device 100. Device 100 has a metal frame 120.Slider 110 is invisible because it is integral with and made from thesame metal as frame 120. Furthermore, slider 110 is flush with and doesnot bulge out or otherwise protrude into or out of frame 120, thereforeit is not visible from the exterior of device 100. Slider 110 has afirst end 190 and a second end 195.

FIG. 7 shows a side cross sectional view of device 100, taken along line7-7 shown in FIG. 6. Metal frame 120 has a face 130. Inside of device100, there is an interior wall 140 below face 130. In between surfaces130 and 140 is a dielectric medium 150, e.g., air. Supports 160 aredisposed between outer surface 130 and interior surface 140. Face 130may have markings (e.g., paint, texture) to indicate the location ofslider 110.

A first pair of capacitor plates 170 and 175 and a second pair ofcapacitor plates 180 and 185 are situated along the left and rightsides, respectively, of invisible slider 110. Upper plate 170 isdisposed on an inner surface of face 130, and capacitor plate 175 isdisposed on a top surface of interior wall 140. Capacitor plates 170 and175 may be attached to, for example, PCBs which are attached to face 130and/or wall 140. In one embodiment, wall 140 is a PCB. In anotherembodiment, capacitor plates 170 and/or 175 can comprise conductivepaint printed on face 130 and wall 140. The second pair of capacitorplates 180 and 185 are disposed similar to the first pair 170 and 175.In the illustrated embodiment, capacitor plates 170/175 and 180/185 areshown as discrete objects attached to face 130 and wall 140. In anotherembodiment (not shown) the face 130 and wall 140 themselves may haveconductive areas and non-conductive areas so as to form a pair ofopposing capacitor plates. When two or more sensors are used, forexample, two or more pairs of capacitor plates, the slider function isenabled.

There is a fixed separation between the opposite capacitor plates ofeach pair (170/175 and 180/185) when slider 110 is not being depressed.This is important because the capacitance, C, between plates 170/175 and180/185 is a function of their separation. Departures from the initialseparation will cause a change in capacitance, ΔC, which can be detectedand processed by device 100. In this embodiment the first pair ofcapacitive plates 170/175 is characterized by C₁ and ΔC₁, while thesecond pair of capacitive plates 180/185 is characterized by C₂ and ΔC₂.As discussed above, the zero-pressure capacitances between plates170/175 and plates 180/185 may be updated to account for changes due toother factors such as temperature, humidity, age of components, etc.

Referring back to FIGS. 1-3, if a user presses down on binary invisiblebutton 20 far enough to meet a threshold change in capacitance, a buttonsignal is detected. In other words, the exact location of the user'sfinger is not critical to the operation of button 20 as long as it isover button 20. Now referring back to FIG. 7, with slider 110, thelocation of the user's finger (or other object) is critical. Slider 110can be correlated with a continuous output scale from 0% to 100% so thatwhen the user presses down on slider 110 10% of the way between itsextreme ends 190 and 195, a function will be commanded at 10% intensity.In one application, slider 110 could be a volume control wherein a usersimply and intuitively presses at (or slides to) the desired volumelevel. In one application, end 190 is correlated to the 100% intensitylevel, while end 195 is correlated to the 0% intensity level. Thisconcept is explained in greater detail below.

When a user presses down on invisible slider 110, the metal outer face130 deflects between supports 160, as shown in FIG. 8. This causes thedistance between capacitor plates 170 and 175 to decrease, with anassociated change in capacitance ΔC₁ between them. A capacitive sensor(not shown) associated with device 100 detects this change. In theillustrated embodiment, the user has pressed down on slider 110 near end190 (i.e., the high intensity end). Note that the separation between thefirst pair of capacitor plates 170/175 has markedly decreased, while theseparation between the second pair of capacitor plates 180/185 hasbarely changed. The capacitive sensor (not shown) therefore detects asmaller change in capacitance ΔC₂ associated with the second pair. Thecapacitive sensor converts these respective changes in capacitance toelectrical signals S₁ and S₂.

At this point, electronics (not shown) associated with device 100 cancompare the signal S₁ generated by the first pair of capacitor plates170/175 with the signal S₂ generated by the second pair of capacitorplates 180/185 in order adjust a continuous output function inaccordance with the exact position along slider 110 of the user'sfinger. One way to do this is by taking a ratio of the two signals. Inthe illustrated embodiment, the separation between the first pair ofcapacitor plates 170/175 is very small and so S₁ will be a large signal.The second pair of capacitive plates 180/185 are relatively unperturbedfrom their initial (neutral) positions. Therefore, the signal theygenerate, S₂, will be very small. Consequently, the ratio S₁:S₂ will beenormous. A large signal ratio can be correlated to having the user'sfinger near end 190. When the user is pressing down near end 190, heintends to command a high intensity, perhaps near 100%. Therefore,device 100 will operate near 100% intensity. This could mean that musicis played loudly, a light comes on brightly, or any other continuousoutput function is commanded to near 100% intensity.

In another implementation, slider 110 can be used to control a scrollingfunction, for example to scroll down (or left/right) a page of text orto scroll through music selections. When the user presses slider 110near end 190, the scroll will go, for example, forward at maximum speed.When the user presses slider 110 near end 195, the scroll will go inreverse at maximum speed. Intermediate positions on slider 110 willcommand a scroll at a lesser speed in the commanded direction (i.e.,forward or reverse). These functions are given by way of example, slider110 can be used to control any continuous output function associatedwith device 100.

If the user presses down near the midpoint of slider 110 (i.e., half waybetween ends 190 and 195), as is shown in FIG. 9, he intends to commanddevice 100 to operate at 50% intensity. Because the first pair ofcapacitor plates 170/175 and the second pair of capacitor plates 180/185are moved closer to each other by approximately equal amounts, they willgenerate approximately equal changes in capacitance compared with theirneutral positions, i.e. ΔC1≈ΔC2. This means that the ratio S₁:S₂ will beapproximately 1:1. A signal ratio of 1:1 is correlated with a commanded50% intensity level.

The 100% and 50% intensity situations are shown in FIGS. 8 and 9. A usercan press slider 110 anywhere between ends 190 and 195 in order tocommand any intensity from 100% to 0%. Furthermore, the ratio S₁:S₂ canbe continuously computed such that the user can continuously slide hisfinger along slider 110 to continuously change the commanded intensitylevel to any desired level, provided sufficient pressure is applied todeflect upper surface 130.

Supports 160 limit the area where a user can activate slider 110. In theillustrated embodiment, if a user presses down to the left of the leftsupport 160, for example, neither pair of capacitor plates 170/175 or180/185 will appreciably move towards each other. Therefore, a change incapacitance (if any) will not exceed the threshold required to registera slider depression. The supports can be closely spaced, thereby makingthe effective area of slider 110 small, or the supports can be widelyspaced, thereby making the effective area of slider 110 large, as isshown in the illustrated embodiment. The configuration of supports 160is shown for illustration only and may be widely varied. For example,there could be two supports, as shown in the illustrated embodiment, orthere could be more than two supports, or only one support. In oneembodiment (not shown), the entire face 130 can function as slider 110if supports 160 are removed. In this implementation, the outer verticalpart of frame 120 functions to keep face 130 and wall 140 separated whenslider 110 is not being depressed. Therefore, supports 160 are notnecessary.

Supports 160 may be etched out of surfaces 130 and/or 140 or they may befree standing. In one embodiment, supports 160 are formed by etching thebottom surface of face 130 so that supports 160 extend downwardly. Inanother embodiment, supports 160 are formed by etching the top surfaceof interior wall 140 so that supports 160 extend upwardly. In anotherembodiment, face 130 and wall 140 and supports 160 are formed by etchingout parts of a monolithic piece. In another embodiment, free standingsupports 160 are affixed to face 130 and wall 140 by techniques known inthe art, for example adhesives, welds, fasteners, etc.

In some embodiments, it may not be desirable to have slider 110 visibleor invisible all the time. As previously mentioned, although face 130may have markings (e.g., paint, texture) to indicate the location ofslider 110, these markings would be visible all of the time and detractfrom the aesthetic simplicity of face 130. To selectively control thevisibility of slider 110, tiny micro-perforations or holes 280 can beformed in face 130 as shown in FIG. 10. Slider 110 can be selectivelybacklit to highlight its location by, for example, shining light throughholes 280. In one embodiment, a light source, for example a lightemitting diode (LED) 290 can be placed on surface 140 under the locationof slider 110. As shown in FIG. 11, the location of slider 110 isvisible when LED 290 is activated.

Invisible slider 110 is depicted as being linear in FIGS. 6-11 for easeof explanation only; however, this is not a limitation. Other shapes arealso possible. For example, in one embodiment an invisible slider can beformed in the shape of a scroll wheel (not shown). Invisible slider 110is depicted as having two pairs of capacitor plates in the figures. Thisis the minimum requirement for the slider functionality, because asdescribed above, the signals from at least two separate capacitivesources can be compared to determine the location of an object placed onthe slider. However, more capacitor plates can be used to give theslider more positional resolution. If for example, three pairs ofcapacitor plates are used, the signals from each of them can be used todetermine the position of an object placed on the slider, and so on.

In one embodiment, the backlight (e.g., LED 290) can be activatedwhenever electronic device 100 is “on.” In another embodiment, thebacklight can be activated as a function of an operating state of device100, for example, when a CD-ROM is inserted, when a memory stick isinserted, and so on, depending on the nature of electronic device 100.In another embodiment, the backlight can be activated as a function ofambient lighting conditions, for example, in low light (dark)conditions. In this embodiment, a light sensor (not shown) may interfacewith LED 290. In another embodiment, the backlight can be activatedcontinuously. In another embodiment, the backlight can be activated whena user taps or presses down on slider 110. In another embodiment, amotion sensor (not shown) may interface with LED 290 and activate itwhen motion is detected. In another embodiment heat and/or sound sensors(not shown) can interface with and activate LED 290 when heat and/orsound is detected.

A pattern (similar to pattern 22 shown in FIG. 5B) of holes 280 can bedisposed on face 130 to indicate the borders of slider 110. This patterncan be formed by, for example, laser cutting through face 130. Holes 280are formed such that they are too small for the unaided human eye todetect; therefore, they appear to be invisible. However, light shiningthrough holes 280 is visible to the naked eye. This gives the impressionthat slider 110 can be made visible or invisible at will.

Conventional touch sensitive track pads require a dielectric outer tracksurface; consequently they, unlike the housing of most electronicdevices, are not made from metal resulting in a clearly visibletransition between housing and track pad. Referring to FIG. 12, aconventional touch-sensitive track pad 200 is shown. A track pad isgenerally a small (often rectangular) area that includes aprotective/cosmetic shield 210 and a plurality of electrodes 220disposed underneath protective shield 210. Electrodes 220 may be locatedon a circuit board, for example a printed circuit board (PCB). For easeof discussion, a portion of protective shield 210 has been removed toshow electrodes 220. Each of the electrodes 220 represents a differentx, y position. In one configuration, an object, such as a finger 230 (oralternately a stylus, not shown) approaches the electrode grid 220, atiny capacitance forms between finger 230 and the electrodes 220proximate the finger 230. The circuit board/sensing electronics (notshown) measures capacitance and produces an x, y input signal 240corresponding to the active electrodes 220 which is sent to a hostdevice 250 (e.g., a computing device) having a display screen 260. Thex, y input signal 240 is used to control the movement of a cursor 270 ondisplay screen 260. As shown, the input pointer moves in a similar x, ydirection as the detected x, y finger motion. Besides moving a cursor,input signal 240 can be used for a variety of functions, for example,making a selection, providing instructions, etc.

Referring now to FIG. 13, a generic electronic device 300 is shown whichapplies the present invention to a track pad. Device 300 features aninvisible track pad 310, whose location is shown in phantom. Track pad310 is used to control some function associated with electronic device300. Device 300 has a metal frame 320. Track pad 310 is invisiblebecause it is integral with and made from the same metal as frame 320.Furthermore, track pad 310 is flush with and does not bulge out orotherwise protrude into or out of frame 320. Therefore, it is notvisible from the exterior of device 300. Frame 320 may have markings(e.g., paint, texture) to indicate the location of track pad 310.

Track pad 310 is similar to slider 110, but track pad 310 has atwo-dimensional matrix of capacitor plate pairs, while slider 110 has aone-dimensional line of capacitor plate pairs (see FIG. 7). Thistwo-dimensional matrix 330 of capacitor plate pairs is seen from abovein FIG. 14. For clarity of explanation, track pad 310 is shown as havinga three by three matrix of capacitor plates; however, the matrix couldbe as small as two by two or could have many more pairs of capacitorplates. Also for clarity of explanation, only capacitor plate pairs 340,350, and 360 are labeled. Supports 370 separate the pairs of capacitorplates, in a similar manner as supports 70 (FIG. 3) and supports 160(FIG. 8) do with invisible button 20 and invisible slider 110.

FIG. 15 is a cross section of device 300 taken along line 15-15 of FIG.13. Metal frame 320 has a face 380. Inside of device 300, there is aninterior wall 390 below face 380. In between face 380 and wall 390 thereis a dielectric medium 400, e.g., air. Each of the capacitor plate pairs340, 350, and 360 are made up of opposing capacitor plates, similar toother embodiments of the present invention. Upper capacitor plates ofeach pair are disposed on an inner surface of face 380, and lowercapacitor plates of each pair are disposed on a surface of interior wall390. These capacitor plates may be attached to, for example, PCBs whichare attached to face 380 and/or wall 390. In one embodiment, wall 390 isa PCB. In another embodiment, capacitor plates pairs 340, 350, and 360can comprise conductive paint printed on face 380 and wall 390. As shownin FIG. 15, the capacitor plates of pairs 340, 350, and 360 are shown asdiscrete objects attached to face 380 and wall 390. In anotherembodiment (not shown) the face 380 and wall 390 themselves may haveconductive areas and non-conductive areas so as to form an array ofpairs of opposing capacitor plates.

There is a fixed separation between the opposite capacitor plates ofeach pair when track pad 310 is not being depressed. This is importantbecause the capacitance, C, between two plates is a function of theirseparation. Departures from the initial separation will cause a changein capacitance, ΔC, which can be detected and processed by device 300.In this embodiment the first pair of capacitive plates 340 arecharacterized by C₁ and ΔC₁, the second pair of capacitive plates 350are characterized by C₂ and ΔC₂, and the third pair of capacitive plates360 are characterized by C₃ and ΔC₃. In the case of a three by threematrix 330 there will be nine capacitances C₁, C₂, C₃, C₄, C₅, C₆, C₇,C₈, C₉ involved as shown in FIG. 16. As discussed above, thezero-pressure capacitances between pairs of capacitive plates in trackpad 310 (e.g., pairs 340, 350, and 360) may be updated to account forchanges due to other factors such as temperature, humidity, age ofcomponents, etc.

Invisible track pad 310 operates in much the same way that invisibleslider 110 does, except now a matrix of nine capacitances (for a threeby three matrix shown in FIGS. 14-16) and nine changes in capacitance isgenerated and processed when a user presses down on the surface of trackpad 310. If a user presses down right on top of capacitor plate pair350, a larger change in capacitance ΔC₂ will result. Changes in theother eight capacitances (see FIG. 16), will be relatively smaller; thisallows device 300 to infer the location of the user's finger on trackpad 310 as being generally in the middle of the pad. As another example,if the user presses down on the bottom right hand corner of track pad310, ΔC₇ will be large, ΔC₁, ΔC₂, and ΔC₈ associated with the nearestneighbor capacitor plate pairs may be moderate, while the other fivechanges in capacitances will be relatively low (or zero). This allowsdevice 300 to infer that the finger is generally on the bottom rightside of track pad 310. And so on. In this way, track pad 310 can commanda tracking function. Using even more pairs of capacitor plates, forexample a ten by twelve matrix, gives device 300 greater positionalresolution but the overall concept remains the same.

As with conventional track pads, invisible track pad 310 can alsocompute the speed of an object scrolling over its surface, and it canalso employ multi-touch technology. Multi-touch consists of a touchsurface (track pad, screen, table, wall, etc.), as well as software thatrecognizes multiple simultaneous touch points, as opposed to thestandard touchscreen (e.g., computer touchpad, ATM), which recognizesonly one touch point.

In some embodiments, it may not be desirable to have track pad 310visible or invisible all the time. As previously mentioned, althoughframe 320 may have markings (e.g., paint, texture) to indicate thelocation of track pad 310, these markings would be visible all of thetime and detract from the aesthetic simplicity of frame 320. Toselectively control the visibility of track pad 310, tinymicro-perforations or holes (not shown) can be formed in frame 320 inthe area of track pad 310. Track pad 310 can be selectively backlit tohighlight its location by, for example, shining light through theinvisible holes. In one embodiment, a light source, for example a lightemitting diode (LED) can be placed on surface 390 under the location oftrack pad 310. As shown in FIG. 17, the location of track pad 310 isvisible when the backlight (LED) is activated.

In one embodiment, the backlight (e.g., LED) can be activated wheneverdevice 300 is “on.” In another embodiment, the backlight can beactivated as a function of an operating state of device 300, forexample, when a CD-ROM is inserted, when a memory stick is inserted, andso on, depending on the nature of electronic device 300. In anotherembodiment, the backlight can be activated as a function of ambientlighting conditions, for example, in low light (dark) conditions. Inthis embodiment, a light sensor (not shown) may interface with thebacklight (LED). In another embodiment, the backlight can be activatedcontinuously. In another embodiment, the backlight can be activated whena user taps or presses down on track pad 310. In another embodiment, amotion sensor (not shown) may interface with the backlight and activateit when motion is detected. In another embodiments heat and/or soundsensors (not shown) can interface with and activate the backlight whenheat and/or sound is detected.

A pattern (similar to pattern 22 shown in FIG. 5B) of holes can bedisposed on frame 320 to indicate the borders of track pad 310. Thispattern can be formed by, for example, laser cutting through frame 320.These holes may be formed such that they are too small for the unaidedhuman eye to detect; therefore, they appear to be invisible. However,light shining through these holes is visible to the naked eye. Thisgives the impression that track pad 310 can be made visible or invisibleat will.

The measurable changes in capacitance caused by changing the separationbetween two capacitor plates, for example plates 80 and 85 (FIGS. 2-4),capacitor plate pairs 170/175 and 180/185 (FIGS. 7-10), and capacitorplate pairs 340, 350, and 360 (FIGS. 14-16) is known as “mutualcapacitance.” Mutual capacitance is but one general method for measuringcapacitance. Another general method is to measure the capacitancebetween a single capacitor plate and a ground reference. This is knownas “capacitance-to-ground.” This can effectively cut in half the numberof capacitor plates necessary in the present invention, as long as thereis a ground reference associated with the remaining capacitor plate(s).Each of these methods involve changing a separation between a capacitorplate and some other “capacitive reference.” In the mutual capacitancemethod, the capacitive reference is a second capacitor plate; in thecapacitance-to-ground method, the capacitive reference is a groundreference. As used herein, a “capacitive reference” is either acapacitor plate or a ground reference.

As used herein, the term “ground” does not imply an actual connection tothe Earth. Rather, a ground is commonly idealized in the electrical artsas an infinite source or sink for charge, which can absorb an unlimitedamount of current without changing its potential. Of course, this isonly an idealization, and as such, many surfaces can be considered a“ground” for purposes of the present invention. The term “ground” is tobe broadly construed. In one embodiment, the frame of an electronicdevice can serve as a ground reference. In another embodiment, a groundreference can be disposed on the frame of an electronic device.

The capacitance-to-ground method can be used in place of the mutualcapacitance methods discussed above. In one embodiment, invisible button20 discussed with reference to FIGS. 1-5 can use capacitance-to-groundinstead of mutual capacitance. In this embodiment, either of capacitorplates 80 or 85 can be removed and replaced by a ground reference. Thecapacitance from the remaining capacitor plate will then be measuredwith respect to ground. As shown in FIG. 18, capacitor plate 80 can beremoved and replaced with ground reference 81, which may be a discretemember disposed on face 40 of frame 30. In another embodiment, capacitorplate 80 can be removed and face 40 itself can be a single groundedplane forming the ground reference, as shown in FIG. 19. The invisiblebuttons of FIGS. 18 and 19 are referred to as 20′ and 20″, respectively.These invisible button will function as previously described, but theyonly need a single capacitor plate (instead of the two necessary formutual capacitance), but they also require a ground reference. Asdiscussed, the face of the frame itself can be the ground reference, ora separate ground reference can be disposed on the frame.

In another embodiment, invisible slider 110 discussed with reference toFIGS. 6-11 can use capacitance-to-ground instead of mutual capacitance.In this embodiment, either of the capacitor plates from each pair(170/175 or 180/185) can be removed and replaced by a ground reference.The capacitance from the remaining capacitor plate will then be measuredwith respect to ground. As shown in FIG. 20, capacitor plates 170 and180 can be removed and replaced with ground references 176 and 186,which may be discrete members disposed on face 130 of frame 120. Inanother embodiment, face 130 itself can be a single grounded planeforming the ground reference, as shown in FIG. 21. The invisible slidersof FIGS. 20 and 21 are referred to as 110′ and 110″, respectively. Theseinvisible sliders win function as previously described, but they onlyneed two capacitor plates (instead of the four necessary for mutualcapacitance), but also require a ground reference(s). As discussed, theface of the frame itself can be the ground reference, or a separateground reference(s) can be disposed on the frame.

In another embodiment, invisible trackpad 310 discussed with referenceto FIGS. 13-17 can use capacitance-to-ground instead of mutualcapacitance. In this embodiment, either of the capacitor plates fromeach pair (e.g., pairs 340, 350, and 360) can be removed and replaced bya ground reference. The capacitance from the remaining capacitor platefrom each pair will then be measured with respect to ground. As shown inFIG. 22, the capacitor plates attached to face 380 from each of pairs340, 350, and 360 can be removed and replaced with ground references341, 351, and 361, which may be discrete members disposed on face 380 offrame 320. In another embodiment, face 380 itself can be a singlegrounded plane forming the ground reference, as shown in FIG. 23. Theinvisible track pads of FIGS. 22 and 23 are referred to as 310′ and310″, respectively. These invisible trackpads will function aspreviously described, but need only nine capacitor plates (instead ofthe eighteen necessary for mutual capacitance using a three by threearray), but they also require a ground reference(s). As discussed, theface of the frame itself can be the ground reference, or a separateground reference(s) can be disposed on the frame.

In other embodiments (not shown), the present invention can includemutual capacitance (i.e., opposing capacitor plates) andcapacitance-to-ground (i.e., a capacitor plate and an opposing groundreference) in the same device.

The invisible input devices described above (button 20, slider 110, andtrack pad 310) can be used in many different implementations. Severalimplementations are described below. These implementations are given byway of example only, and not by way of limitation. The person of skillin the art recognizes that the present invention has wide applicability.

The present invention can be used, in one embodiment, as a closed-lidexternal button for a laptop computer. Referring now to FIG. 24, laptopcomputer 4800 is shown with its lid 4802 closed. Lid 4802 may be, forexample, aluminum. Lid 4802 has an array of invisible status indicators4804. Status indicators 4804 could, for example, indicate the presenceof and level (signal strength) of a wi-fi signal, or they could indicatebattery strength. Lid 4802 has an invisible button 4806 (shown inphantom) that functions even when lid 4802 is closed. Button 4806 isbased on capacitive sensing. When a user presses lid 4802 at thelocation of button 4806 lid 4802 deforms in that area and causes achange in capacitance, which in turn causes invisible status indicators4804 to light up according to the level of wi-fi signal (or batterystrength, etc.). Either of invisible button 4806 or invisible statusindicators 4804 can employ invisible holes and backlighting to make themselectively visible or invisible to the user.

Referring now to FIG. 25, in another embodiment, laptop computer 4900has an invisible button 4902 which may function as a closed-lid modestate change button. In one implementation, pressing button 4902 cansignal a component of laptop 4900 or an associated external component to“wakeup” from a closed-lid “sleep” mode to a closed-lid “active” mode.For example, pressing button 4902 when laptop computer 4900 is in theclosed-lid sleep mode, can wake up an external monitor (not shown), syncan iPod or iPhone (not shown) with laptop computer 4900, or installsoftware to laptop computer 4900 while lid 4904 is closed. In anotherimplementation, in visible button 4902 can shutdown laptop computer 4900from the closed-lid sleep or closed-lid active modes.

In another embodiment, the present invention can be used to replacetraditional track pads and/or traditional track pad buttons withinvisible buttons or invisible track pads. Referring now to FIG. 26,laptop computer 5000 is shown with lid 5002 open. Track pad 5004 has atrack surface 5006 for scrolling and a button 5008 for clicking. Inconventional track pads, track surface 5006 and button 5008 are normallyseparate components. Button 5008 can be replaced with an invisiblebutton, which gives laptop 5000 a more seamless and attractive look. Thetrack surface 5006 itself can even be replaced with an invisible trackpad, such as invisible track pad 310 discussed with reference to FIGS.13-17.

In another embodiment, invisible controls can be added to laptopcomputer 5000 using the present invention. In one implementation,invisible control 5009 is shown in FIG. 26. Invisible control 5009 maybe used, for example, to control music or video stored and played fromcomputer 5000. Invisible control may have, for example, rewind 5010,play 5012, and fast forward 5014 invisible buttons and it may haveincrease 5016 and decrease 5018 invisible volume controls. Invisibleholes may form patterns indicative of the functions of these buttons(e.g., rewind arrow, play arrow, fast forward arrow, volume increaseplus, volume decrease minus, etc.). The holes may be backlit.

Invisible control 5009 may be a contextual control, meaning that thefunction of control 5009 is dependent upon an operating state of thedevice (in this case laptop computer 5000). The backlight may also beactivated as a function of the operating state of the device. Forexample, control 5009 becomes visible automatically when a DVD isinserted into computer 5000, when a music CD is insert into computer5000, or when iTunes® is active. The function of control 5009 is thenadapted to either play the DVD, play the music CD, or to control iTunes®functions. iTunes® is a trade mark for a digital media playerapplication created by Apple Inc. of Cupertino, Calif. In otherimplementations, invisible contextual controls (not shown) can be usedto deactivate a camera, eject a disk or USB stick, or to illuminate thekeyboard depending on the state of laptop 5000. Each of these invisiblecontextual controls can be made to become visible under appropriatesituations (e.g., when the camera is on, the disk or USB stick is in, orif it is dark, respectively). Even the entire keyboard 5020 can bereplaced with an array of invisible buttons. In fact, all of theconventional keys, buttons, track pads, etc. on a laptop or otherelectronic device can be replaced by invisible inputs according to thepresent invention. In this way, the truly seamless design has become areality.

While this invention has been described in terms of several preferredembodiments, there are alterations, permutations, and equivalents, whichfall within the scope of this invention. It should also be noted thatthere are many alternative ways of implementing the methods andapparatuses of the present invention. It is therefore intended that thefollowing appended claims be interpreted as including all suchalterations, permutations, and equivalents as fall within the truespirit and scope of the present invention.

What is claimed is:
 1. A laptop computing device, comprising: a housing;a display coupled to the housing; a keyboard coupled to the housing; atrackpad coupled to the housing; and a touch-operated control region,proximate to the keyboard, forming a portion of the housing; thetouch-operated control region being illuminable to indicate a functionof the touch-operated control region.
 2. The laptop computing device ofclaim 1, wherein the housing forms an input surface of thetouch-operated control region.
 3. The laptop computing device of claim1, wherein a function associated with the touch-operated control regionis configurable.
 4. The laptop computing device of claim 1, wherein thetouch-operated control region includes multiple capacitor plates andactivation of the touch-operated control region changes a capacitancebetween the multiple capacitor plates.
 5. The laptop computing device ofclaim 1, wherein an input surface of the touch-operated control regionis formed of a same material as the housing.
 6. An electronic device,comprising: a first enclosure; a display coupled to the first enclosure;a second enclosure connected to the first enclosure; a keyboard coupledto the second enclosure; a trackpad coupled to the second enclosure; anda touch input area on the second enclosure; wherein illumination of thetouch input area indicates a function identified on the touch inputarea.
 7. The electronic device of claim 6, wherein a function associatedwith the touch input area is dependent on an operating state of theelectronic device.
 8. The electronic device of claim 6, wherein thetouch input area includes holes extending through the second enclosure.9. The electronic device of claim 8, wherein a light source isconfigured to illuminate the holes.
 10. The electronic device of claim9, wherein the holes are visually imperceptible when not illuminated bythe light source.
 11. The electronic device of claim 9, wherein thelight source illuminates the holes when a function associated with thetouch input area becomes available.
 12. The electronic device of claim6, wherein the portion of the second enclosure is flexible.
 13. Anelectronic device, comprising: a housing portion; keys coupled to thehousing portion; a trackpad coupled to the housing portion; and a touchcontrol surface, forming an exterior portion of the housing portion ofthe electronic device, the touch control surface being visuallyimperceptible when a function is not indicated on the control surface;the touch control surface being visible to indicate a functionidentified on the control surface when touched.
 14. The electronicdevice of claim 13, wherein the touch control surface is a contextualcontrol.
 15. The electronic device of claim 13, wherein the touchcontrol surface is a metal surface.
 16. The electronic device of claim13, wherein the touch control surface deforms when force is applied. 17.The electronic device of claim 13, wherein the electronic devicecomprises an external keyboard.
 18. The electronic device of claim 13,wherein the touch control surface comprises a capacitive touch surface.